Many vehicles include a security system, remote keyless entry system, and/or remote start system which permit a user to perform a function when away from the vehicle. For example, the security system may be switched between armed and disarmed modes by operation of a small handheld remote transmitter. Similarly, remote keyless entry and remote engine starting features can be similarly performed using a suitable remote transmitter. Typically such transmitters are dedicated and sold as part of the overall remote control system. Such systems can be factory installed or added as aftermarket accessories.
A number of patents relate to using a cellular telephone as a remote transmitter for operating a vehicle control system, such as for example, U.S. Pat. No. 5,612,878 to Joao et al. In other words, in such a system, the cellular telephone can be used as the remote transmitter to control a function at the vehicle.
Similarly, U.S. Pat. No. 5,815,557 to Larson also discloses a cellular telephone which transmits to a lock and wherein the user operates the buttons of the telephone as he would buttons on a key card to gain access to the secured area. U.S. Pat. No. 5,276,728 to Pagliaroli et al. discloses a vehicle security system including a short range portable transmitter that may be used to transmit a command code to the receiver which may be in the same frequency ranges as the cellular telephone transmitters. U.S. Pat. Nos. 5,370,201 to Inubshi, U.S. Pat. No. 5,535,844 to Samford, and U.S. Pat. No. 5,917,405 to Joao also disclose a cellular telephone communicating with a receiver at the vehicle.
Unfortunately, none of the above identified prior art patents address how a cellular telephone or its associated vehicle receiver can be configured to operate together easily and while providing security from unauthorized operation by other cellular telephones. In addition, these cellular telephones typically require the use of intervening cellular communications infrastructure, i.e., relay towers or base stations, when used as a remote transmitter. The use of relay towers or base stations by a cellular telephone often results in an expense to the user.